forked from bonzini/smalltalk
/
Tokenizer.st
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/
Tokenizer.st
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"======================================================================
|
| Generic tokenizer superclass.
|
|
======================================================================"
"======================================================================
|
| Copyright 1999, 2000, 2001 Free Software Foundation, Inc.
| Written by Paolo Bonzini.
|
| This file is part of GNU Smalltalk.
|
| GNU Smalltalk is free software; you can redistribute it and/or modify it
| under the terms of the GNU General Public License as published by the Free
| Software Foundation; either version 2, or (at your option) any later version.
|
| GNU Smalltalk is distributed in the hope that it will be useful, but WITHOUT
| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
| FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
| details.
|
| You should have received a copy of the GNU General Public License along with
| GNU Smalltalk; see the file COPYING. If not, write to the Free Software
| Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
======================================================================"
FileStream fileIn: Directory kernel, '/../examples/PushBack.st'!
Stream subclass: #Tokenizer
instanceVariableNames: 'stream line'
classVariableNames: 'CR LF'
poolDictionaries: ''
category: 'Examples-Useful'!
!Tokenizer class methodsFor: 'initialization'!
initialize
CR := Character cr.
LF := Character nl
!
!Tokenizer class methodsFor: 'instance creation'!
on: aFileName
^self new init: (FileStream open: aFileName mode: 'r')
!
onStream: aStream
^self new init: aStream
! !
!Tokenizer methodsFor: 'accessing'!
isFileStream
^self stream isKindOf: FileStream
!
stream
^stream stream
! !
!Tokenizer methodsFor: 'stream compatibility'!
position
^stream position
!
close
stream close
!
nextPut: notUsed
self shouldNotImplement
!
next
| ch tok |
[ stream atEnd ifTrue: [ ^self atEndToken ].
ch := self nextChar.
tok := self tokenize: ch.
tok isNil ] whileTrue: [ ].
^tok
!
atEnd
^stream atEnd
!
close
stream close
! !
!Tokenizer methodsFor: 'parsing tokens'!
atEndToken
^nil
!
tokenize: ch
"This must answer a token. The tokens' starting char is
passed in ch"
self subclassResponsibility
! !
!Tokenizer methodsFor: 'utility methods'!
line
^line
!
peekChar
^stream peek
!
peekChar: aChar
| next |
(next := stream next) == aChar ifTrue: [ ^true ].
stream putBack: next.
^false
!
putBack: aChar
stream putBack: aChar.
! !
!Tokenizer methodsFor: 'recording'!
nextChar
| c |
c := stream next.
c == CR ifTrue: [ line := line + 1. stream peekFor: LF ].
c == LF ifTrue: [ line := line + 1 ].
^c
! !
!Tokenizer methodsFor: 'private'!
init: aStream
stream := PushBackStream on: aStream.
line := 1.
! !
Tokenizer initialize!